This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

The neon signs from Las Vegas' past find their final resting place at this unusual graveyard.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

Yup, that's a 330-foot yacht passing over the highway.

Massive puppet-automaton machines created by French artist collective Machines de l’Ile.

The narrowest street in Paris.

A gregarious Ohio resident has been building his whimsical temple to peace for decades.

A unique attraction and museum dedicated to exploring iconic roadside structures.

This magnificent 18th-century hall consists of a maze of nearly a thousand interconnected passages.

Hundreds of enormous icebergs drift through this waterway every year.

This mother-daughter run curiosities shop is a beautifully odd mix of taxidermy and exotic plants.

These medieval funerary monuments are now home to a colony of critically endangered vultures.

Step into a cartoon at this Seoul café that aims to evoke a two-dimensional scene.

This 8th-century Bavarian monastery is home to an exquisite Baroque-era library.

Yale University's home for rare works, including the mysterious Voynich Manuscript.

Peek through a transparent pyramid and drink in the mountain made of books.

Sandstone rock formations that look like they belong on the cover of a progressive rock album.

Community bookshelf of 25-foot-tall book spines.

Limestone caves with spectacular showcase chambers.

This beloved Baltimore spot features caged dolls, a giant Pez collection, and many, many mannequins.

An encyclopedic collection of mammal penises.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

These layered sandstone mountains in China look like they are made of pressed crayons.

Live data is transmitted from the Atlantic coast to instantly recreate the ocean waves in this fountain at the NOAA headquarters.